Females Are Genetically Protected from Autism

Posted on March 11, 2014

It takes more mutations to trigger autism in women than in men, which may explain why men are four times more likely to have the disorder

It takes more mutations to trigger autism in women than in men, which may explain why men are four times more likely to have the disorder, according to a study published 26 February in the American Journal of Human Genetics.

The study found that women with autism or developmental delay tend to have more large disruptions in their genomes than do men with the disorder. Inherited mutations are also more likely to be passed down from unaffected mothers than from fathers.

"This strongly argues that females are protected from autism and developmental delay and require more mutational load, or more mutational hits that are severe, in order to push them over the threshold," says lead researcher Evan Eichler, professor of genome sciences at the University of Washington in Seattle. "Males on the other hand are kind of the canary in the mineshaft, so to speak, and they are much less robust."

The findings bolster those from previous studies, but don't explain what confers protection against autism in women. The fact that autism is difficult to diagnose in girls may mean that studies enroll only those girls who are severely affected and who may therefore have the most mutations, researchers note.